A delauney triangulation problem.

Hello,
i am not very well conversant with MAthematica. But I want to solve a
problem with the Mathematica. It is as follows.
I have to draw a mesh of triangles. The mesh may not be isotropic in
2D( perfect 2D mesh = identical equilateral triangles joined to one
another forming a hexagonal lattice structure). The mesh I desire
mostly should consist of identical equilateral triangles joined to one
another but few of the triangles should be isosceles . This would
introduce inhomogeneity into the 2D lattice structure.
I hope I have made myself clear. This is actually a practical problem
as we see such structures when magnetic field penetrates certain type
of Superconductors.
If anyone can provide me some hints of how to progress I would be
extremely grateful.
Thanking you,
Yours Sincerely,
Nilay Saha
Kamerlingh Onnes Lab,
Leiden Univ,
2300RA Leiden,
Postbus : 9506
Phone: (0031)71 527 5476
e-mail: saha@rulkol.leidenuniv.nl